Determination of Ten Pesticide Residues in Tea by Liquid Chromatography-Tandem Mass Spectrometry and Gas Chromatography-Tandem Mass Spectrometry

The method was developed for the determination of six pesticide residues (acetamiprid, dimethoate, imidacloprid, methomyl, pirimiphos-methyl and procymidone) in tea by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and another method was developed for the determination of seven pesticide residues (deltamethrin, dimethoate, lambda-cyhalothrin, p, p'-DDE, pirimiphos-methyl, procymidone and pyridaben) in tea by gas chromatography-tandem mass spectrometry (GC-MS/MS).Dimethoate, pirimiphos-methyl and procymidone were suitable for determination by both methods. The calibration curves showed good linearity in 5~200 μg/L for the six pesticides by LC-MS/MS (R²>0.995). The average recoveries ranged from 70.0%~105.0% with the relative standard deviations of 0.3%~18.7% at the spiked levels of 10, 50, 100 μg/kg. The calibration curves showed good linearity in 10~500 μg/L for the seven pesticides by GC-MS/MS (R²>0.996). The average recoveries ranged from 82.0%~110.0% with the relative standard deviations of 1.8%~12.0% at the spiked levels of 10, 50, 300 μg/kg. The method improved the detection of 10 pesticide residues in tea, and the sensitivity met the requirement of foreign limit standard, which was suitable for the determination of pesticide residues in tea.